Understanding temperature, motion, gravity, energy, and light is essential for the ASVAB science test. This guide provides detailed explanations and real-world examples to help you master these concepts.
1. Temperature Measurements: Comparing Different Scales 🌡️
Temperature measures heat energy and is expressed in different units. Scientists use Kelvin, while most of the world uses Celsius, and the U.S. primarily uses Fahrenheit.
| Scale | Symbol | Used In | Freezing Point of Water | Boiling Point of Water |
| Celsius | °C | Science, most countries | 0°C | 100°C |
| Fahrenheit | °F | USA | 32°F | 212°F |
| Kelvin | K | Science, physics | 273K | 373K |
🔹 Absolute Zero (0K or -273°C): The lowest possible temperature where all atomic motion stops. It is impossible to reach absolute zero, but scientists have come close in controlled lab settings.
Example Conversions:
- C → F: (°C × 9/5) + 32 = °F
- F → C: (°F – 32) × 5/9 = °C
- C → K: °C + 273 = K
🔹 Example:
A hot summer day might be 90°F, which converts to 32°C and 305K.
2. Newton’s Laws of Motion: How Objects Move 🏎️
Sir Isaac Newton developed three fundamental laws that describe how forces affect motion. These laws apply everywhere, from sports to space travel.
Newton’s First Law (Law of Inertia) 🚀
“An object at rest stays at rest, and an object in motion stays in motion unless acted upon by an outside force.”
- The more mass an object has, the harder it is to change its motion.
- Friction and air resistance are everyday forces that slow things down.
🔹 Example:
- A book on a table stays still until someone pushes it.
- A rolling soccer ball keeps moving until friction (grass) or a player stops it.
Newton’s Second Law (Force & Acceleration) 🔄
“Force = Mass × Acceleration (F = ma)”
- The greater the force, the greater the acceleration.
- The more mass something has, the more force it takes to move it.
🔹 Example:
- Pushing an empty shopping cart is easier than pushing a full cart because the full cart has more mass.
- A fast baseball pitch exerts more force than a slow one.
Newton’s Third Law (Action & Reaction) ⚖️
“For every action, there is an equal and opposite reaction.”
- Forces always act in pairs.
🔹 Example:
- A rocket pushes exhaust downward, and the rocket moves upward.
- When you jump, your feet push down on the ground, and the ground pushes you up.
3. Newton’s Law of Universal Gravitation 🌍⬇️
“Every object in the universe attracts every other object with a force proportional to their masses and inversely proportional to the square of the distance between them.”
Key Facts About Gravity:
- More mass = More gravitational pull. (Earth has more gravity than the Moon.)
- Greater distance = Weaker gravitational force. (Planets farther from the Sun orbit slower.)
🔹 Example:
- The Moon stays in orbit around Earth due to Earth’s gravitational pull.
- Astronauts weigh less on the Moon because it has only 1/6th of Earth’s gravity.
4. The Speed of Light: The Universe’s Speed Limit ⚡
Light travels at an incredible speed, moving faster than anything else in the universe.
- Speed of Light (c) = 186,000 miles per second (299,792 km/s).
- Light from the Sun takes 8 minutes to reach Earth.
- Einstein’s Theory of Relativity (E=mc²) states that nothing can travel faster than light.
🔹 Examples:
- When you look at the stars, you’re seeing light from the past (some stars are thousands of light-years away).
- Space travel is limited because reaching other stars would take thousands of years with current technology.
5. Kinetic vs. Potential Energy: Stored vs. Moving Energy
Energy is the ability to do work and comes in two main forms:
| Type of Energy | Definition | Example |
| Kinetic Energy 🚗 | Energy of motion | A moving car, a falling apple |
| Potential Energy 🎢 | Stored energy (waiting to be used) | A stretched rubber band, water in a dam |
Formulas:
- Kinetic Energy (KE) = ½ mv²
- Potential Energy (PE) = mgh (Mass × Gravity × Height)
🔹 Example:
A bowstring pulled back has potential energy; when released, the arrow gains kinetic energy.
6. Types of Kinetic & Potential Energy
- Types of Kinetic Energy (Motion Energy) 🚀
| Type | Description | Example |
| Mechanical ⚙️ | Movement of objects | Running, gears turning |
| Thermal 🔥 | Heat energy (moving molecules) | Boiling water, fire |
| Radiant ☀️ | Light energy (electromagnetic waves) | Sunlight, X-rays |
| Electrical ⚡ | Moving electrons | Lightning, power lines |
| Sound 🎵 | Vibrations in air | Music, a speaker playing |
🔹 Example:
- A wind turbine converts mechanical kinetic energy (wind) into electrical energy.
B. Types of Potential Energy (Stored Energy) 🎢
| Type | Description | Example |
| Gravitational 🌍 | Energy stored due to height | A roller coaster at the top of a hill |
| Elastic 🏹 | Energy stored in stretched/compressed objects | A pulled-back bowstring |
| Chemical 🔋 | Energy stored in chemical bonds | Food, batteries, gasoline |
| Nuclear ☢️ | Energy stored in atomic nuclei | Nuclear reactors, the Sun |
🔹 Example:
- Gasoline has chemical potential energy, which converts to kinetic energy when burned in an engine.
7. Key Takeaways:
✅ Temperature: Kelvin, Celsius, and Fahrenheit are used to measure heat energy.
✅ Newton’s Laws: Explain motion, force, and reactions.
✅ Gravity: The more massive an object, the stronger its gravity.
✅ Speed of Light: The fastest thing in the universe (186,000 miles/sec).
✅ Kinetic Energy = Motion, Potential Energy = Stored energy.